Böhmische Lochkovium-Bivalven vom östlichen Anti-Atlas (Unter-Devon, Marokko)

Abstract

32 species of bivales are desribed from the lowermost Devonian of the eastern Anti-Atlas, Morocco. The majority of the species are closely related to the species described from Perunica (Prague Basin, Bohemia) and the Northern Gondwana marginal regions (Sardinia, Massif Armoricain, and the Carnic Alps). Two new species (Panenka hollardi n. sp. andVevoda tada n. sp.) are characteristic to the Anti-Atlas. The bivalve dominated communities, known also from Bohemia, Sardinia, Massif Armoricain, and the Carnic Alps are closely related to the cephalopod limestone biofacies and micritic limestone facies. In practice they may be used for the correlation with Perunica and other Gondwanan European basins. Analyses of the Bivalve dominated communities shows that the development of the Anti-Atlas during the Lower Devonian, Lochkovian was very similar to other Northern Gondwana regions and that the distance between Perunica and Northern Gondwana was much smaller than it has been interpreted on the basis of paleomagnetic measurements. In Gondwanan Europe and in Perunica the Silurian type cephalopod limestone facies is developed only up to the lowermost Lochkovian. In Morocco, the cephalopod limestone facies of this type is developed in several other levels higher in the Devonian, at least up to the upper Lochkovian. This may be caused by the paleogeographic position of Morocco during the Lower Devonian being in the same position as the Gondwanan Massif Armoricain, Sardinia, Carnic Alps and Perunican Prague Basin were during the Silurian. They all shifted together during the Lower Devonian to the equatorial region while Morocco changed its position to the temperate region just south of the equatorial region.